1. Field of the Invention
The present invention relates to A wire electrical discharge machine. More particularly, the present invention relates to a wire electrical discharge machine capable of efficiently collecting machined chips which are machined products produced by electric discharge machining.
2. Description of the Prior Art
In a wire electrical discharge machine, voltage is Applied between a work piece and a wire electrode while relatively moving the wire electrode and the work piece, electricity is discharged therebetween, thereby machining the work piece. Machined chips which will become a product (machined product) obtained by this electric discharge machining and machined cuttings generated by electric discharge machining are drop into a wide machining tank, and the widely scattered machining chips and machining cuttings are manually collected after the machining.
As indicated in Japanese Utility Model Registration No. 2504638, there is proposed A method in which a product cut out from a work piece by electric discharge machining is collected by a main body of the wire electrical discharge machine or a transfer body such as an exterior robot.
However, it is extremely difficult to precisely position and collect machined chips which were cut out separately at arbitrary positions of the work piece. Especially if machined chips as products are small, it is almost impossible to collect all the chips.
There is a collecting method using magnetic or absorbing system, but there is a limit in shape, size, quantity and weight, and since precise positioning is required, such a collecting method is used only for a specific shape.
In a continuous machining using a wire electrical discharge machine, in order to cut out, products as many as possible from a limited sized expensive work piece, the most efficient machining method is to form a machining path in a form of one line as shown in FIG. 1A, and to sequentially cut out the machined products such that cutting margins or edges are not remained as much as possible.
FIGS. 1A to 1C show examples in which small chips 2 which will become machined products and which are triangular as viewed from above on a PCD (sintered diamond) disk 1 which is work piece are to be cut out by the wire electrical discharge machine. FIG. 1A is a plan view, FIG. 1B is a side view thereof and FIG. 1C shows the shape of the small chips obtained by the electrical discharge machine.
The machining path 4 of the wire electrode with respect to the work piece 1 is formed in a form of one line, and a plurality of machined chips 2 are cut out by this machining path 4. In FIG. 1A, a reference number 3 represents machined cutting which were not cut, and a reference number 5 represents a clamp member for grasping a disk 1 of the work piece.
In the case of such an electric discharge machining, small machined chips 2 and machined cuttings 3 which were cut out by jet stream of machining liquid during machining scatter into a machining tank. To collect the cut machined scatter into a machining tank. To collect the cut machined chips 2 and machined cuttings 3, there is conventionally no method except manually collecting after completion of all the machining operations, and it is difficult to collect them. Especially if machined chips which will be products and machined cuttings are small, they easily enter a narrow gap in a machining tank of a wire electrical discharge machine, and the chips and cuttings can not be collected, or they enter sliding surface of a mechanism in a machining tank, and there is a problem in that they may damage mechanical parts.
For example, when small machined chips 2 are cut out from a disk 1 of a CBN (Cubic Boron Nitride) sintered body or PCD (Polycrystalline Diamond) sintered body, since a unit price of the disk 1 of the work piece is expensive, a unit price of the machined chip 2 as a product becomes also expensive. If the expensive machined chips can not be collected, this is a serious problem.
Generally, PCD sintered body disk 1 has a diameter of about 60 to 70 mm and a thickness of about 1.6 to 3.2 mm. The machined chip 2 as a product in the cutting machining shown in FIG. 1A is rectangular in shape of about minimum 1 mm, usually about 2 mm xc3x974 mm, or triangular in shape of 3 mm in many cases. About 300 pieces of machined chip 2 can be cut and produced form one sheet of disk.
As shown in FIGS. 3A and 3B, the machined chips shown in this example are used as a blade on a tip end of a bite 6 of a lathe or used as a blade of an end mill or a reamer 7. Machined chips 2 cut out by the electric discharge machining have various shapes as shown in FIG. 2.
When machined chips 2 which are small machined products as described above are cut out by cutting machining, as shown in FIG. 4, some of the cut machined chips 2 and machined cuttings 3 drop into a machining tank 8, and other jump by jet stream of machining liquid and scatter onto a work table 9 or the like to which the clamp member 6 which grasps a work piece 1 is mounted. In FIG. 4, reference numbers 10 and 11 respectively represent an upper wire guide and a lower wire guide for guiding a wire electrode 12, and reference numbers 13 and 14 represent a nozzle for jetting machining liquid provided in the upper guide 10 and the lower guide 11 into a machining region.
Conventionally, machined chips 2 of the machined products are collected manually after completion of all machining operations. Even if one machine chip can be collected for 1 second, if there exists 300 pieces of machined chips, it takes five minutes, which remarkably reduces the operating efficiency. Further, operation for checking in a machining tank 8 thoroughly to confirm if there are any uncollected chips, which takes about 30 minutes or more, is required in the prior art. This confirming operation is a simple operation, which required patience and causes anguish. Further, in case where various shaped machined chips are machined as described above, whenever different shaped chips are machined, they must be collected, which takes time. If different shaped chips are mixed, it is necessary to distinguish the chips after collection, and this operation is tough.
As described above, when small machined products are machined by cutting machining, it takes time to collect the machined products, which remarkably reduces the operating efficiency of the wire electrical discharge machine.
The object of the present invention is to provide a wire electrical discharge machine which facilitates collection of machined products cut out by wire electric discharge machining.
To attain the above object, a wire electrical discharge machine of the present invention comprises receiving means for receiving machined chips to be cut out by electric discharge machining. The receiving means is disposed so as to cover a portion at least lower than a portion where electric discharge machining is carried out, or both the portion and a side, and the machined chips are prevented from passing through the receiving means, while machining liquid is allowed to pass through the receiving means.
Especially, a wire electrical discharge machine comprises an upper nozzle disposed above a work piece and a lower nozzle disposed below the work piece, in which a wire electrode is inserted between the upper nozzle and the lower nozzle, the wire electrode and the work piece are relatively moved with respect to each other to machine the work piece, thereby forming machined chips, wherein at least the lower nozzle or a lower guide to which the lower nozzle is mounted is provided with lower receiving means prevents the machined chips from passing therethrough and allows machining liquid to pass therethrough. This structure makes it easy to collect the machined chips.
Upper receiving means is mounted to an upper nozzle or an upper guide to which the upper nozzle is mounted so as to be opposed to the lower receiving means, combined receiving means configured by combining lower receiving means and the upper receiving means is formed at least during machining, and the machined chips are received by the combined receiving means. The work piece is to be grasped by a clamp member, the combined receiving means receives the work piece and the clamp member which grasps the work piece, and the combined receiving means has a gap for allowing the clamp member to come into and out of the combined receiving means. A resilient machined chip-stopping member is provided in the upper receiving means at the gap for preventing the machined chips from jumping out of the combined receiving means through the gap. The receiving means has a reticulated or porous structure such that machining liquid passes through the receiving means and the receiving means receives the machined chips. At least the lower receiving means receives the machined chips. At least the lower receiving means is detachably mounted to the lower nozzle or the lower guide to which the lower nozzle is mounted.
Further, in a wire electrical discharge machine in which a wire nozzle and wire guides are disposed laterally in a horizontal direction, and a wire electrode horizontally held by the wire guide and a vertically clamped work piece are moved relatively with respect to each other to machine the work piece, thereby generating machined chips is mounted to the wire nozzle or the wire guide, and the receiving means receives the machined chips. In this case, the receiving means is mounted to each of the left and right wire nozzles and wire guides, the left and right receiving means are abutted against with each other during machining, and when machined chips are taken out, the left and right receiving means are separated from each other.